ac/nir: Set speculatable for buffer loads where allowed
[mesa.git] / src / amd / common / ac_nir_to_llvm.c
index 61b33c74e6c4f1921379b41ef5849a5096b3e055..dffaeedfbb42b5c5e81d0ca4f0f65a647a956086 100644 (file)
@@ -38,6 +38,7 @@ struct ac_nir_context {
        struct ac_shader_abi *abi;
 
        gl_shader_stage stage;
+       shader_info *info;
 
        LLVMValueRef *ssa_defs;
 
@@ -112,7 +113,7 @@ get_ac_image_dim(const struct ac_llvm_context *ctx, enum glsl_sampler_dim sdim,
        enum ac_image_dim dim = get_ac_sampler_dim(ctx, sdim, is_array);
 
        if (dim == ac_image_cube ||
-           (ctx->chip_class <= VI && dim == ac_image_3d))
+           (ctx->chip_class <= GFX8 && dim == ac_image_3d))
                dim = ac_image_2darray;
 
        return dim;
@@ -371,7 +372,7 @@ static LLVMValueRef emit_f2f16(struct ac_llvm_context *ctx,
        src0 = ac_to_float(ctx, src0);
        result = LLVMBuildFPTrunc(ctx->builder, src0, ctx->f16, "");
 
-       if (ctx->chip_class >= VI) {
+       if (ctx->chip_class >= GFX8) {
                LLVMValueRef args[2];
                /* Check if the result is a denormal - and flush to 0 if so. */
                args[0] = result;
@@ -382,10 +383,10 @@ static LLVMValueRef emit_f2f16(struct ac_llvm_context *ctx,
        /* need to convert back up to f32 */
        result = LLVMBuildFPExt(ctx->builder, result, ctx->f32, "");
 
-       if (ctx->chip_class >= VI)
+       if (ctx->chip_class >= GFX8)
                result = LLVMBuildSelect(ctx->builder, cond, ctx->f32_0, result, "");
        else {
-               /* for SI/CIK */
+               /* for GFX6-GFX7 */
                /* 0x38800000 is smallest half float value (2^-14) in 32-bit float,
                 * so compare the result and flush to 0 if it's smaller.
                 */
@@ -572,8 +573,7 @@ static void visit_alu(struct ac_nir_context *ctx, const nir_alu_instr *instr)
                src[i] = get_alu_src(ctx, instr->src[i], src_components);
 
        switch (instr->op) {
-       case nir_op_fmov:
-       case nir_op_imov:
+       case nir_op_mov:
                result = src[0];
                break;
        case nir_op_fneg:
@@ -1032,10 +1032,17 @@ static void visit_alu(struct ac_nir_context *ctx, const nir_alu_instr *instr)
                LLVMValueRef in[3];
                for (unsigned chan = 0; chan < 3; chan++)
                        in[chan] = ac_llvm_extract_elem(&ctx->ac, src[0], chan);
-               results[0] = ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.cubetc",
+               results[0] = ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.cubesc",
                                                ctx->ac.f32, in, 3, AC_FUNC_ATTR_READNONE);
-               results[1] = ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.cubesc",
+               results[1] = ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.cubetc",
                                                ctx->ac.f32, in, 3, AC_FUNC_ATTR_READNONE);
+               LLVMValueRef ma = ac_build_intrinsic(&ctx->ac, "llvm.amdgcn.cubema",
+                                                    ctx->ac.f32, in, 3, AC_FUNC_ATTR_READNONE);
+               results[0] = ac_build_fdiv(&ctx->ac, results[0], ma);
+               results[1] = ac_build_fdiv(&ctx->ac, results[1], ma);
+               LLVMValueRef offset = LLVMConstReal(ctx->ac.f32, 0.5);
+               results[0] = LLVMBuildFAdd(ctx->ac.builder, results[0], offset, "");
+               results[1] = LLVMBuildFAdd(ctx->ac.builder, results[1], offset, "");
                result = ac_build_gather_values(&ctx->ac, results, 2);
                break;
        }
@@ -1162,9 +1169,9 @@ get_buffer_size(struct ac_nir_context *ctx, LLVMValueRef descriptor, bool in_ele
                LLVMBuildExtractElement(ctx->ac.builder, descriptor,
                                        LLVMConstInt(ctx->ac.i32, 2, false), "");
 
-       /* VI only */
-       if (ctx->ac.chip_class == VI && in_elements) {
-               /* On VI, the descriptor contains the size in bytes,
+       /* GFX8 only */
+       if (ctx->ac.chip_class == GFX8 && in_elements) {
+               /* On GFX8, the descriptor contains the size in bytes,
                 * but TXQ must return the size in elements.
                 * The stride is always non-zero for resources using TXQ.
                 */
@@ -1259,7 +1266,7 @@ static LLVMValueRef lower_gather4_integer(struct ac_llvm_context *ctx,
                                              LLVMConstInt(ctx->i32, 0x14000000, false), "");
 
                /* replace the NUM FORMAT in the descriptor */
-               tmp2 = LLVMBuildAnd(ctx->builder, tmp2, LLVMConstInt(ctx->i32, C_008F14_NUM_FORMAT_GFX6, false), "");
+               tmp2 = LLVMBuildAnd(ctx->builder, tmp2, LLVMConstInt(ctx->i32, C_008F14_NUM_FORMAT, false), "");
                tmp2 = LLVMBuildOr(ctx->builder, tmp2, tmp, "");
 
                args->resource = LLVMBuildInsertElement(ctx->builder, args->resource, tmp2, ctx->i32_1, "");
@@ -1369,7 +1376,7 @@ static LLVMValueRef build_tex_intrinsic(struct ac_nir_context *ctx,
                break;
        }
 
-       if (instr->op == nir_texop_tg4 && ctx->ac.chip_class <= VI) {
+       if (instr->op == nir_texop_tg4 && ctx->ac.chip_class <= GFX8) {
                nir_deref_instr *texture_deref_instr = get_tex_texture_deref(instr);
                nir_variable *var = nir_deref_instr_get_variable(texture_deref_instr);
                const struct glsl_type *type = glsl_without_array(var->type);
@@ -1388,6 +1395,22 @@ static LLVMValueRef build_tex_intrinsic(struct ac_nir_context *ctx,
        }
 
        args->attributes = AC_FUNC_ATTR_READNONE;
+       bool cs_derivs = ctx->stage == MESA_SHADER_COMPUTE &&
+                        ctx->info->cs.derivative_group != DERIVATIVE_GROUP_NONE;
+       if (ctx->stage == MESA_SHADER_FRAGMENT || cs_derivs) {
+               /* Prevent texture instructions with implicit derivatives from being
+                * sinked into branches. */
+               switch (instr->op) {
+               case nir_texop_tex:
+               case nir_texop_txb:
+               case nir_texop_lod:
+                       args->attributes |= AC_FUNC_ATTR_CONVERGENT;
+                       break;
+               default:
+                       break;
+               }
+       }
+
        return ac_build_image_opcode(&ctx->ac, args);
 }
 
@@ -1432,7 +1455,7 @@ static LLVMValueRef visit_load_push_constant(struct ac_nir_context *ctx,
                }
        }
 
-       ptr = ac_build_gep0(&ctx->ac, ctx->abi->push_constants, addr);
+       ptr = LLVMBuildGEP(ctx->ac.builder, ctx->abi->push_constants, &addr, 1, "");
 
        if (instr->dest.ssa.bit_size == 8) {
                unsigned load_dwords = instr->dest.ssa.num_components > 1 ? 2 : 1;
@@ -1528,11 +1551,11 @@ static unsigned get_cache_policy(struct ac_nir_context *ctx,
 {
        unsigned cache_policy = 0;
 
-       /* SI has a TC L1 bug causing corruption of 8bit/16bit stores.  All
+       /* GFX6 has a TC L1 bug causing corruption of 8bit/16bit stores.  All
         * store opcodes not aligned to a dword are affected. The only way to
         * get unaligned stores is through shader images.
         */
-       if (((may_store_unaligned && ctx->ac.chip_class == SI) ||
+       if (((may_store_unaligned && ctx->ac.chip_class == GFX6) ||
             /* If this is write-only, don't keep data in L1 to prevent
              * evicting L1 cache lines that may be needed by other
              * instructions.
@@ -1568,9 +1591,10 @@ static void visit_store_ssbo(struct ac_nir_context *ctx,
 
                u_bit_scan_consecutive_range(&writemask, &start, &count);
 
-               /* Due to an LLVM limitation, split 3-element writes
-                * into a 2-element and a 1-element write. */
-               if (count == 3) {
+               /* Due to an LLVM limitation with LLVM < 9, split 3-element
+                * writes into a 2-element and a 1-element write. */
+               if (count == 3 &&
+                   (elem_size_bytes != 4 || !ac_has_vec3_support(ctx->ac.chip_class, false))) {
                        writemask |= 1 << (start + 2);
                        count = 2;
                }
@@ -1598,13 +1622,11 @@ static void visit_store_ssbo(struct ac_nir_context *ctx,
                if (num_bytes == 1) {
                        ac_build_tbuffer_store_byte(&ctx->ac, rsrc, data,
                                                    offset, ctx->ac.i32_0,
-                                                   cache_policy & ac_glc,
-                                                   writeonly_memory);
+                                                   cache_policy & ac_glc);
                } else if (num_bytes == 2) {
                        ac_build_tbuffer_store_short(&ctx->ac, rsrc, data,
                                                     offset, ctx->ac.i32_0,
-                                                    cache_policy & ac_glc,
-                                                    writeonly_memory);
+                                                    cache_policy & ac_glc);
                } else {
                        int num_channels = num_bytes / 4;
 
@@ -1612,6 +1634,9 @@ static void visit_store_ssbo(struct ac_nir_context *ctx,
                        case 16: /* v4f32 */
                                data_type = ctx->ac.v4f32;
                                break;
+                       case 12: /* v3f32 */
+                               data_type = ctx->ac.v3f32;
+                               break;
                        case 8: /* v2f32 */
                                data_type = ctx->ac.v2f32;
                                break;
@@ -1627,8 +1652,7 @@ static void visit_store_ssbo(struct ac_nir_context *ctx,
                                                    num_channels, offset,
                                                    ctx->ac.i32_0, 0,
                                                    cache_policy & ac_glc,
-                                                   false, writeonly_memory,
-                                                   false);
+                                                   false, false);
                }
        }
 }
@@ -1636,22 +1660,12 @@ static void visit_store_ssbo(struct ac_nir_context *ctx,
 static LLVMValueRef visit_atomic_ssbo(struct ac_nir_context *ctx,
                                       const nir_intrinsic_instr *instr)
 {
+       LLVMTypeRef return_type = LLVMTypeOf(get_src(ctx, instr->src[2]));
        const char *op;
-       char name[64];
+       char name[64], type[8];
        LLVMValueRef params[6];
        int arg_count = 0;
 
-       if (instr->intrinsic == nir_intrinsic_ssbo_atomic_comp_swap) {
-               params[arg_count++] = ac_llvm_extract_elem(&ctx->ac, get_src(ctx, instr->src[3]), 0);
-       }
-       params[arg_count++] = ac_llvm_extract_elem(&ctx->ac, get_src(ctx, instr->src[2]), 0);
-       params[arg_count++] = ctx->abi->load_ssbo(ctx->abi,
-                                                get_src(ctx, instr->src[0]),
-                                                true);
-       params[arg_count++] = ctx->ac.i32_0; /* vindex */
-       params[arg_count++] = get_src(ctx, instr->src[1]);      /* voffset */
-       params[arg_count++] = ctx->ac.i1false;  /* slc */
-
        switch (instr->intrinsic) {
        case nir_intrinsic_ssbo_atomic_add:
                op = "add";
@@ -1687,16 +1701,37 @@ static LLVMValueRef visit_atomic_ssbo(struct ac_nir_context *ctx,
                abort();
        }
 
-       if (HAVE_LLVM >= 0x900 &&
-           instr->intrinsic != nir_intrinsic_ssbo_atomic_comp_swap) {
+       if (instr->intrinsic == nir_intrinsic_ssbo_atomic_comp_swap) {
+               params[arg_count++] = ac_llvm_extract_elem(&ctx->ac, get_src(ctx, instr->src[3]), 0);
+       }
+       params[arg_count++] = ac_llvm_extract_elem(&ctx->ac, get_src(ctx, instr->src[2]), 0);
+       params[arg_count++] = ctx->abi->load_ssbo(ctx->abi,
+                                                 get_src(ctx, instr->src[0]),
+                                                 true);
+
+       if (HAVE_LLVM >= 0x900) {
+               /* XXX: The new raw/struct atomic intrinsics are buggy with
+                * LLVM 8, see r358579.
+                */
+               params[arg_count++] = get_src(ctx, instr->src[1]); /* voffset */
+               params[arg_count++] = ctx->ac.i32_0; /* soffset */
+               params[arg_count++] = ctx->ac.i32_0; /* slc */
+
+               ac_build_type_name_for_intr(return_type, type, sizeof(type));
                snprintf(name, sizeof(name),
-                        "llvm.amdgcn.buffer.atomic.%s.i32", op);
+                        "llvm.amdgcn.raw.buffer.atomic.%s.%s", op, type);
        } else {
+               params[arg_count++] = ctx->ac.i32_0; /* vindex */
+               params[arg_count++] = get_src(ctx, instr->src[1]); /* voffset */
+               params[arg_count++] = ctx->ac.i1false; /* slc */
+
+               assert(return_type == ctx->ac.i32);
                snprintf(name, sizeof(name),
                         "llvm.amdgcn.buffer.atomic.%s", op);
        }
 
-       return ac_build_intrinsic(&ctx->ac, name, ctx->ac.i32, params, arg_count, 0);
+       return ac_build_intrinsic(&ctx->ac, name, return_type, params,
+                                 arg_count, 0);
 }
 
 static LLVMValueRef visit_load_buffer(struct ac_nir_context *ctx,
@@ -1744,11 +1779,12 @@ static LLVMValueRef visit_load_buffer(struct ac_nir_context *ctx,
                                                         cache_policy & ac_glc);
                } else {
                        int num_channels = util_next_power_of_two(load_bytes) / 4;
+                       bool can_speculate = access & ACCESS_CAN_REORDER;
 
                        ret = ac_build_buffer_load(&ctx->ac, rsrc, num_channels,
                                                   vindex, offset, immoffset, 0,
                                                   cache_policy & ac_glc, 0,
-                                                  false, false);
+                                                  can_speculate, false);
                }
 
                LLVMTypeRef byte_vec = LLVMVectorType(ctx->ac.i8, ac_get_type_size(LLVMTypeOf(ret)));
@@ -2399,10 +2435,12 @@ static void get_image_coords(struct ac_nir_context *ctx,
 }
 
 static LLVMValueRef get_image_buffer_descriptor(struct ac_nir_context *ctx,
-                                                const nir_intrinsic_instr *instr, bool write)
+                                                const nir_intrinsic_instr *instr,
+                                               bool write, bool atomic)
 {
        LLVMValueRef rsrc = get_image_descriptor(ctx, instr, AC_DESC_BUFFER, write);
-       if (ctx->abi->gfx9_stride_size_workaround) {
+       if (ctx->abi->gfx9_stride_size_workaround ||
+           (ctx->abi->gfx9_stride_size_workaround_for_atomic && atomic)) {
                LLVMValueRef elem_count = LLVMBuildExtractElement(ctx->ac.builder, rsrc, LLVMConstInt(ctx->ac.i32, 2, 0), "");
                LLVMValueRef stride = LLVMBuildExtractElement(ctx->ac.builder, rsrc, LLVMConstInt(ctx->ac.i32, 1, 0), "");
                stride = LLVMBuildLShr(ctx->ac.builder, stride, LLVMConstInt(ctx->ac.i32, 16, 0), "");
@@ -2448,15 +2486,15 @@ static LLVMValueRef visit_image_load(struct ac_nir_context *ctx,
                unsigned num_channels = util_last_bit(mask);
                LLVMValueRef rsrc, vindex;
 
-               rsrc = get_image_buffer_descriptor(ctx, instr, false);
+               rsrc = get_image_buffer_descriptor(ctx, instr, false, false);
                vindex = LLVMBuildExtractElement(ctx->ac.builder, get_src(ctx, instr->src[1]),
                                                 ctx->ac.i32_0, "");
 
-               /* TODO: set "can_speculate" when OpenGL needs it. */
+               bool can_speculate = access & ACCESS_CAN_REORDER;
                res = ac_build_buffer_load_format(&ctx->ac, rsrc, vindex,
                                                  ctx->ac.i32_0, num_channels,
                                                  !!(args.cache_policy & ac_glc),
-                                                 false);
+                                                 can_speculate);
                res = ac_build_expand_to_vec4(&ctx->ac, res, num_channels);
 
                res = ac_trim_vector(&ctx->ac, res, instr->dest.ssa.num_components);
@@ -2502,7 +2540,7 @@ static void visit_image_store(struct ac_nir_context *ctx,
        args.cache_policy = get_cache_policy(ctx, access, true, writeonly_memory);
 
        if (dim == GLSL_SAMPLER_DIM_BUF) {
-               LLVMValueRef rsrc = get_image_buffer_descriptor(ctx, instr, true);
+               LLVMValueRef rsrc = get_image_buffer_descriptor(ctx, instr, true, false);
                LLVMValueRef src = ac_to_float(&ctx->ac, get_src(ctx, instr->src[3]));
                unsigned src_channels = ac_get_llvm_num_components(src);
                LLVMValueRef vindex;
@@ -2516,8 +2554,7 @@ static void visit_image_store(struct ac_nir_context *ctx,
 
                ac_build_buffer_store_format(&ctx->ac, rsrc, src, vindex,
                                             ctx->ac.i32_0, src_channels,
-                                            args.cache_policy & ac_glc,
-                                            writeonly_memory);
+                                            args.cache_policy & ac_glc, false);
        } else {
                args.opcode = ac_image_store;
                args.data[0] = ac_to_float(&ctx->ac, get_src(ctx, instr->src[3]));
@@ -2546,11 +2583,11 @@ static LLVMValueRef visit_image_atomic(struct ac_nir_context *ctx,
        MAYBE_UNUSED int length;
 
        enum glsl_sampler_dim dim;
-       bool is_unsigned;
+       bool is_unsigned = false;
        bool is_array;
        if (bindless) {
-               if (instr->intrinsic == nir_intrinsic_image_atomic_min ||
-                   instr->intrinsic == nir_intrinsic_image_atomic_max) {
+               if (instr->intrinsic == nir_intrinsic_bindless_image_atomic_min ||
+                   instr->intrinsic == nir_intrinsic_bindless_image_atomic_max) {
                        const GLenum format = nir_intrinsic_format(instr);
                        assert(format == GL_R32UI || format == GL_R32I);
                        is_unsigned = format == GL_R32UI;
@@ -2614,11 +2651,14 @@ static LLVMValueRef visit_image_atomic(struct ac_nir_context *ctx,
        params[param_count++] = get_src(ctx, instr->src[3]);
 
        if (dim == GLSL_SAMPLER_DIM_BUF) {
-               params[param_count++] = get_image_buffer_descriptor(ctx, instr, true);
+               params[param_count++] = get_image_buffer_descriptor(ctx, instr, true, true);
                params[param_count++] = LLVMBuildExtractElement(ctx->ac.builder, get_src(ctx, instr->src[1]),
                                                                ctx->ac.i32_0, ""); /* vindex */
                params[param_count++] = ctx->ac.i32_0; /* voffset */
-               if (HAVE_LLVM >= 0x800) {
+               if (HAVE_LLVM >= 0x900) {
+                       /* XXX: The new raw/struct atomic intrinsics are buggy
+                        * with LLVM 8, see r358579.
+                        */
                        params[param_count++] = ctx->ac.i32_0; /* soffset */
                        params[param_count++] = ctx->ac.i32_0;  /* slc */
 
@@ -2750,11 +2790,11 @@ static void emit_membar(struct ac_llvm_context *ac,
 
 void ac_emit_barrier(struct ac_llvm_context *ac, gl_shader_stage stage)
 {
-       /* SI only (thanks to a hw bug workaround):
+       /* GFX6 only (thanks to a hw bug workaround):
         * The real barrier instruction isn’t needed, because an entire patch
         * always fits into a single wave.
         */
-       if (ac->chip_class == SI && stage == MESA_SHADER_TESS_CTRL) {
+       if (ac->chip_class == GFX6 && stage == MESA_SHADER_TESS_CTRL) {
                ac_build_waitcnt(ac, LGKM_CNT & VM_CNT);
                return;
        }
@@ -2876,14 +2916,12 @@ static LLVMValueRef visit_var_atomic(struct ac_nir_context *ctx,
        LLVMValueRef result;
        LLVMValueRef src = get_src(ctx, instr->src[src_idx]);
 
+       const char *sync_scope = HAVE_LLVM >= 0x0900 ? "workgroup-one-as" : "workgroup";
+
        if (instr->intrinsic == nir_intrinsic_shared_atomic_comp_swap ||
            instr->intrinsic == nir_intrinsic_deref_atomic_comp_swap) {
                LLVMValueRef src1 = get_src(ctx, instr->src[src_idx + 1]);
-               result = LLVMBuildAtomicCmpXchg(ctx->ac.builder,
-                                               ptr, src, src1,
-                                               LLVMAtomicOrderingSequentiallyConsistent,
-                                               LLVMAtomicOrderingSequentiallyConsistent,
-                                               false);
+               result = ac_build_atomic_cmp_xchg(&ctx->ac, ptr, src, src1, sync_scope);
                result = LLVMBuildExtractValue(ctx->ac.builder, result, 0, "");
        } else {
                LLVMAtomicRMWBinOp op;
@@ -2928,9 +2966,7 @@ static LLVMValueRef visit_var_atomic(struct ac_nir_context *ctx,
                        return NULL;
                }
 
-               result = LLVMBuildAtomicRMW(ctx->ac.builder, op, ptr, ac_to_integer(&ctx->ac, src),
-                                           LLVMAtomicOrderingSequentiallyConsistent,
-                                           false);
+               result = ac_build_atomic_rmw(&ctx->ac, op, ptr, ac_to_integer(&ctx->ac, src), sync_scope);
        }
        return result;
 }
@@ -3419,6 +3455,26 @@ static void visit_intrinsic(struct ac_nir_context *ctx,
        case nir_intrinsic_quad_swap_diagonal:
                result = ac_build_quad_swizzle(&ctx->ac, get_src(ctx, instr->src[0]), 3, 2, 1 ,0);
                break;
+       case nir_intrinsic_quad_swizzle_amd: {
+               uint32_t mask = nir_intrinsic_swizzle_mask(instr);
+               result = ac_build_quad_swizzle(&ctx->ac, get_src(ctx, instr->src[0]),
+                                              mask & 0x3, (mask >> 2) & 0x3,
+                                              (mask >> 4) & 0x3, (mask >> 6) & 0x3);
+               break;
+       }
+       case nir_intrinsic_masked_swizzle_amd: {
+               uint32_t mask = nir_intrinsic_swizzle_mask(instr);
+               result = ac_build_ds_swizzle(&ctx->ac, get_src(ctx, instr->src[0]), mask);
+               break;
+       }
+       case nir_intrinsic_write_invocation_amd:
+               result = ac_build_writelane(&ctx->ac, get_src(ctx, instr->src[0]),
+                                           get_src(ctx, instr->src[1]),
+                                           get_src(ctx, instr->src[2]));
+               break;
+       case nir_intrinsic_mbcnt_amd:
+               result = ac_build_mbcnt(&ctx->ac, get_src(ctx, instr->src[0]));
+               break;
        default:
                fprintf(stderr, "Unknown intrinsic: ");
                nir_print_instr(&instr->instr, stderr);
@@ -3538,13 +3594,13 @@ static LLVMValueRef get_sampler_desc(struct ac_nir_context *ctx,
 
 /* Disable anisotropic filtering if BASE_LEVEL == LAST_LEVEL.
  *
- * SI-CI:
+ * GFX6-GFX7:
  *   If BASE_LEVEL == LAST_LEVEL, the shader must disable anisotropic
  *   filtering manually. The driver sets img7 to a mask clearing
  *   MAX_ANISO_RATIO if BASE_LEVEL == LAST_LEVEL. The shader must do:
  *     s_and_b32 samp0, samp0, img7
  *
- * VI:
+ * GFX8:
  *   The ANISO_OVERRIDE sampler field enables this fix in TA.
  */
 static LLVMValueRef sici_fix_sampler_aniso(struct ac_nir_context *ctx,
@@ -3553,7 +3609,7 @@ static LLVMValueRef sici_fix_sampler_aniso(struct ac_nir_context *ctx,
        LLVMBuilderRef builder = ctx->ac.builder;
        LLVMValueRef img7, samp0;
 
-       if (ctx->ac.chip_class >= VI)
+       if (ctx->ac.chip_class >= GFX8)
                return samp;
 
        img7 = LLVMBuildExtractElement(builder, res,
@@ -3572,6 +3628,7 @@ static void tex_fetch_ptrs(struct ac_nir_context *ctx,
 {
        nir_deref_instr *texture_deref_instr = NULL;
        nir_deref_instr *sampler_deref_instr = NULL;
+       int plane = -1;
 
        for (unsigned i = 0; i < instr->num_srcs; i++) {
                switch (instr->src[i].src_type) {
@@ -3581,6 +3638,9 @@ static void tex_fetch_ptrs(struct ac_nir_context *ctx,
                case nir_tex_src_sampler_deref:
                        sampler_deref_instr = nir_src_as_deref(instr->src[i].src);
                        break;
+               case nir_tex_src_plane:
+                       plane = nir_src_as_int(instr->src[i].src);
+                       break;
                default:
                        break;
                }
@@ -3589,10 +3649,18 @@ static void tex_fetch_ptrs(struct ac_nir_context *ctx,
        if (!sampler_deref_instr)
                sampler_deref_instr = texture_deref_instr;
 
-       if (instr->sampler_dim  == GLSL_SAMPLER_DIM_BUF)
-               *res_ptr = get_sampler_desc(ctx, texture_deref_instr, AC_DESC_BUFFER, &instr->instr, false, false);
-       else
-               *res_ptr = get_sampler_desc(ctx, texture_deref_instr, AC_DESC_IMAGE, &instr->instr, false, false);
+       enum ac_descriptor_type main_descriptor = instr->sampler_dim  == GLSL_SAMPLER_DIM_BUF ? AC_DESC_BUFFER : AC_DESC_IMAGE;
+
+       if (plane >= 0) {
+               assert(instr->op != nir_texop_txf_ms &&
+                      instr->op != nir_texop_samples_identical);
+               assert(instr->sampler_dim  != GLSL_SAMPLER_DIM_BUF);
+
+               main_descriptor = AC_DESC_PLANE_0 + plane;
+       }
+
+       *res_ptr = get_sampler_desc(ctx, texture_deref_instr, main_descriptor, &instr->instr, false, false);
+
        if (samp_ptr) {
                *samp_ptr = get_sampler_desc(ctx, sampler_deref_instr, AC_DESC_SAMPLER, &instr->instr, false, false);
                if (instr->sampler_dim < GLSL_SAMPLER_DIM_RECT)
@@ -3725,7 +3793,7 @@ static void visit_tex(struct ac_nir_context *ctx, nir_tex_instr *instr)
         * It's unnecessary if the original texture format was
         * Z32_FLOAT, but we don't know that here.
         */
-       if (args.compare && ctx->ac.chip_class >= VI && ctx->abi->clamp_shadow_reference)
+       if (args.compare && ctx->ac.chip_class >= GFX8 && ctx->abi->clamp_shadow_reference)
                args.compare = ac_build_clamp(&ctx->ac, ac_to_float(&ctx->ac, args.compare));
 
        /* pack derivatives */
@@ -3844,7 +3912,13 @@ static void visit_tex(struct ac_nir_context *ctx, nir_tex_instr *instr)
                args.offset = NULL;
        }
 
-       /* TODO TG4 support */
+       /* DMASK was repurposed for GATHER4. 4 components are always
+        * returned and DMASK works like a swizzle - it selects
+        * the component to fetch. The only valid DMASK values are
+        * 1=red, 2=green, 4=blue, 8=alpha. (e.g. 1 returns
+        * (red,red,red,red) etc.) The ISA document doesn't mention
+        * this.
+        */
        args.dmask = 0xf;
        if (instr->op == nir_texop_tg4) {
                if (instr->is_shadow)
@@ -4320,6 +4394,7 @@ void ac_nir_translate(struct ac_llvm_context *ac, struct ac_shader_abi *abi,
        ctx.abi = abi;
 
        ctx.stage = nir->info.stage;
+       ctx.info = &nir->info;
 
        ctx.main_function = LLVMGetBasicBlockParent(LLVMGetInsertBlock(ctx.ac.builder));
 
@@ -4365,7 +4440,7 @@ ac_lower_indirect_derefs(struct nir_shader *nir, enum chip_class chip_class)
         * by the reality that LLVM 5.0 doesn't have working VGPR indexing
         * on GFX9.
         */
-       bool llvm_has_working_vgpr_indexing = chip_class <= VI;
+       bool llvm_has_working_vgpr_indexing = chip_class <= GFX8;
 
        /* TODO: Indirect indexing of GS inputs is unimplemented.
         *